Everyday Research Methods

Be quiet! Psychological effects of noise

In one of the studies, researchers found that students whose classrooms were on the train-track side of the school made less progress in reading than those on the quieter side.  Credit: Alon Adika/Shutterstock

The weekly Freakonomics podcast recently put together an episode about the psychological impact of loud noises in our environment. You can listen to it (or read the transcript) here. 

The host and guest review several studies with a variety of methodologies, which include some excellent examples of quasi-experiments.

The introduction to the transcript reads, 

The modern world overwhelms us with sounds we didn’t ask for, like car alarms and cell-phone “halfalogues.” What does all this noise cost us in terms of productivity, health, and basic sanity?

 

Example I.

The first example comes from animal behavior and behavioral ecologist Peter Tyack, who studied whales in the Bay of Fundy. The Bay provided lots of food for the whales, but as a site of many shipping channels, the same place always had the background noise of ships going to and fro. 

Researchers like Tyack had never really thought much about this background noise. It was just there. But then all of a sudden it wasn’t. The change came with the 9/11 terrorist attacks.

TYACK: All of a sudden, the ships that were plying the ocean in that area stopped. 

This drop in ship traffic was only temporary. But it happened to coincide with some other whale research that was happening in the Bay of Fundy:

TYACK: Researchers from the New England Aquarium had been sampling feces from whales to look at stress hormones. It wasn’t part of a noise experiment at all. 

It was just your standard whale-feces research.

TYACK: But what they found was that if you compared the stress hormones in whales before 9/11 and after 9/11, their stress hormones actually went down after 9/11. 

a) In the quasi-experiment described here, what is the quasi-independent variable? What are its levels? What is the dependent variable?

b) Let's assume that the researchers collected and tested whale feces nearly every day, several days before 9/11 and several days afterwards, as well. What type of quasi-experiment is it (nonequivalent control groups, nonequivalent control group prettest-posttest, nonequivalent control groups interrupted time series, nonequivalent control groups interrupted time series)?  

c) Sketch a graph of the results of the whale study. 

Example 2

Here's another example: This one took place in a public school in New York City. The school was built right next to an elevated subway track, so kids in one of the school were exposed to the loud noise of subway trains approximately every four minutes. 

One side of the school building faced a nearby elevated subway; the other side faced away. Bronzaft matched second-, fourth-, and sixth-grade classrooms on the quiet side and on the noisy side, where a passing train would push the sound readings from 59 decibels to 89 decibels. Then she compared the average reading scores from the two sets of classrooms.

BRONZAFT: And the children exposed to the transit noise were nearly a year behind in reading by the sixth grade, and the teacher had difficulty teaching.

d) In the quasi-experiment described here, what is the quasi-independent variable? What are its levels? What is the dependent variable?

e)  What type of quasi-experiment is it (nonequivalent control groups, nonequivalent control group prettest-posttest, nonequivalent control groups interrupted time series, nonequivalent control groups interrupted time series)?  

f) Sketch a graph of the results of the reading study. 

g) In the podcast, they make two caveats:

It’s worth noting that Bronzaft’s subway research, as with similar studies at airports and elsewhere, have some limitations. For one thing, Bronzaft couldn’t randomly assign students to the noisy versus quieter classrooms. There were also relatively few classrooms to choose from, so there might have been some natural variation.

Which of the four big validities is the first caveat about? Which of the four big validities is the second caveat about?  How big of a problem would this be? 

Follow up: Bronzaft conducted and published additional studies, in which, after noise reduction efforts (such as adding acoustic tiles and treating the rails), children on the train-side of the building and children on quiet side of the building were reading at the same level.  

Would you like to read more about the effects of noise on child development and mental health? Visit this resource. There's also an educational module available about the effects of sound in NYC here.

 

 

Will an "awe walk" do wonders for your well-being?

The study asked all volunteers to go on a daily walk, but randomly assigned only some of them to seek out experiences of awe.  Credit: Studio Grand Web/Shutterstock

A recent headline reads, "An 'awe walk' might do wonders for your well-being."  Here is the journalist's summary of an empirical journal article.

The journalist starts by explaining that psychological researchers already know that exercise can improve mood. And we also already know that a feeling of awe can improve mental health. The journalist introduces the concept:

A somewhat nebulous emotion, awe generally is defined as the sense that you are in the presence of something larger and more consequential than yourself and that this something is mysterious and ineffable. 

In the study,

They concentrated on people in their 60s, 70s and 80s, an age when some people can face heightened risks for declining mental health.

Read the journalist's description of the study, identifying the study's independent variable, dependent variables (there are more than one DV), and control variable(s):

The scientists asked 52 of the study volunteers if they would mind adding a weekly 15-minute walk to their normal schedules. ...Fresh, baseline studies of their mental health showed they were psychologically well-adjusted as well, with little anxiety or depression.

The scientists randomly divided these volunteers into two groups. One, as a control group, was asked to start walking, at least once a week, for 15 minutes, preferably outside, but given few other mandates.

The members of the other group likewise were asked to walk once a week, but also were instructed in how to cultivate awe as they walked.

Not surprisingly, they found that the awe walkers seemed to have become adept at discovering and amplifying awe. One volunteer reported focusing now on “the beautiful fall colors and the absence of them among the evergreen forest.” A control walker, in contrast, said she spent much of a recent walk fretting about an upcoming vacation and “all the things I had to do before we leave.”

The researchers also found small but significant differences in the groups’ sense of well-being. Over all, the awe walkers felt happier, less upset and more socially connected than the men and women in the control group. The volunteers in the control group reported some improvements in mood, but their gains were slighter.

Questions

a) What was this study's IV? What were its levels? Was the IV manipulated as independent groups or within groups? 

b) Name three distinct DVs from this study, based on the journalist's description.

c) Which type of experiment is this? Posttest only? prettest-posttest? repeated measures? concurrent measures?

d)  Pick one of the DVs you listed in (b). Sketch a bar graph of this DVs. (Hint: you are going to need to plot four data points--do you see why?).

e) Construct validity question: What's going on in the paragraph that starts, "Not surprisingly, they found that the awe walkers seemed to have become adept at discovering and amplifying awe."? Use the term "manipulation check" in your response, and explain why a manipulation check is relevant to construct validity.

f) Statistical validity question: The journalist describes "small but significant differences". What does this phrase mean? Use the term "effect size" in your answer. 

g) External validity question: Can we generalize from this sample, or is generalization unknown? defend your answer (but please don't refer to sample size!)

h) Internal validity question: What role did random assignment play in this study? What if somebody says, "some people just like going for walks"--would you consider this to be a threat to internal validity? Why or why not? 

The journalist also mentions another DV. The researchers asked people to take a couple of selfies during their walks:

Over the course of the eight weeks, the size of awe walkers’ countenances shrank in relation to the scenery around them. Their faces grew smaller, the world larger. Nothing similar occurred in the photos from the control group.

i) It sounds like the researchers did not preregister prediction about the selfie content. Is lack of preregistration a potential problem?